Explanation:
This galaxy is having a bad millennium.
In fact, the past 100 million years haven't been so good,
and probably the next billion or so will be quite tumultuous.
Visible on the upper left, NGC 4038 used to be a normal spiral galaxy, minding its own business, until NGC 4039, toward its right,
crashed into it.
The evolving wreckage, known famously as
the Antennae, is pictured above.
As gravity
restructures each galaxy, clouds of gas slam into each other,
bright blue knots of stars form, massive stars form and
explode,
and brown filaments of dust are strewn about.
Eventually the
two galaxies
will converge into one larger spiral galaxy.
Such collisions are not unusual, and even our own
Milky Way Galaxy
has undergone several in the past and is
predicted to collide
with our neighboring
Andromeda Galaxy in a few billion years.
The
frames that
compose this image
were taken by the orbiting Hubble Space Telescope by professional astronomers to
better understand galaxy collisions.
These frames -- and many other deep space images from
Hubble -- have since been
made public,
allowing an interested amateur to download and
process
them into this visually stunning composite.